Grinding water tank unit for use in processing eyeglass lens, device for separating processing debris, and eyeglass lens processing apparatus having the tank unit or device

ABSTRACT

A grinding water tank unit which enables reuse of grinding water that has been used for processing an eyeglass lens, includes: a tank in which the grinding water is stored; a filter, disposed in the tank, for filtering the grinding water to be separate from processing debris, the filter having a sealed hollow portion; a first water suction pump; and a first water suction passage which connects the hollow portion to the first pump, and through which the grinding water filtered by the filter is sucked by suction of the first pump.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The invention relates to an eyeglass lens processing apparatusfor processing eyeglass lenses; to a grinding water tank unit forstoring and circulating grinding water; and to a processing debrisseparator for separating grinding water from processing debris.

[0003] 2. Description of the Related Art

[0004] Grinding water is fed to an eyeglass lens processing apparatus inorder to cool a portion of a lens to be processed and remove debrisproduced during the course of processing the lens. A water-supply methodemployed in this connection may be classified into a waterline directcoupling method for supplying water from a waterline directly to aprocessing apparatus main unit; and a circulation method. According tothe circulation method, grinding water stored in a tank is pumped up andfed to the processing apparatus main unit using a pump. Grinding waterhaving been used is drained into the tank, and the grinding water isthen reused.

[0005] The waterline direct coupling method presents a problem ofprocessing debris being drained directly into sewage from the processingapparatus main unit together with used grinding water. Even thecirculation method suffers a problem of difficulty in completelyseparating processing debris from grinding water, thereby requiringeffort in removing solely processing debris. Another problem of thecirculation method lies in that a portion of processing debris isdrained into a sewage along with the grinding water stored in the tankat the time of replacement of grinding water.

[0006] When a plastic lens is processed, bubbles develop in drainedgrinding water. Particularly, when the eyeglass processing apparatus ofcirculation type performs processing operation over a period of time,the tank is filled with bubbles, sometimes resulting in leakage ofbubbles from the tank or overflow of bubbles to a processing chamber ofthe processing apparatus main unit. For this reason, replacement ofgrinding water and cleaning of inside of the tank must be performed atfrequent intervals.

SUMMARY OF THE INVENTION

[0007] In light of the drawback in the related art, an object of theinvention is to provide an apparatus capable of readily separatinggrinding water in a tank from processing debris.

[0008] Another object of the invention is to provide an apparatuscapable of diminishing the amount of bubbles developing in a tank.

[0009] To solve the drawback, the invention is characterized by thefollowing arrangements.

[0010] (1) A grinding water tank unit which enables reuse of grindingwater that has been used for processing an eyeglass lens, comprising:

[0011] a tank in which the grinding water is stored;

[0012] a filter, disposed in the tank, for filtering the grinding waterto be separate from processing debris, the filter having a sealed hollowportion;

[0013] a first water suction pump; and

[0014] a first water suction passage which connects the hollow portionto the first pump, and through which the grinding water filtered by thefilter is sucked by suction of the first pump.

[0015] (2) The tank unit according to (1), wherein the filter includes asubstantially plate-like filter which is disposed at a bottom of thetank, and which has a filter surface substantially equal in area to aninterior bottom surface of the tank.

[0016] (3) The tank unit according to (2), wherein the filter has thehollow portion defined between the filter and the interior bottomsurface of the tank.

[0017] (4) The tank unit according to (1), further comprising:

[0018] a first water supply passage which connects the first pump to thetank, and through which the grinding water sucked by the first pump issupplied to the tank.

[0019] (5) The tank unit according to (1), further comprising:

[0020] an antifoaming device for eliminating bubbles developing in thetank.

[0021] (6) The tank unit according to (5), wherein the antifoamingdevice has a water ejection opening disposed at a predetermined heightin the tank, and eliminates the bubbles using water pressure of waterejected from the water ejection opening.

[0022] (7) The tank unit according to (6), further comprising:

[0023] a second water suction pump;

[0024] a second water suction passage which connects the tank to thesecond pump, and through which the grinding water in the tank is suckedby suction of the second pump; and

[0025] a second water supply passage which connects the second pump tothe water ejection opening, and through which the grinding water suckedby the second pump is supplied to the water ejection opening.

[0026] (8) The tank unit according to (6), wherein an ejection directionof the water ejection opening is changeable.

[0027] (9) An eyeglass lens processing apparatus for processing aneyeglass lens, comprising:

[0028] a processing chamber in which a lens grinding tool is disposed;

[0029] a tank in which grinding water is stored;

[0030] a drain passage through which the grinding water is drained fromthe processing chamber to the tank;

[0031] a filter, disposed in the tank, for filtering the grinding waterto be separate from processing debris, the filter having a sealed hollowportion;

[0032] a water suction pump; and

[0033] a water suction passage which connects the hollow portion to thepump, and through which the grinding water filtered by the filter issucked by suction of the pump.

[0034] (10) The eyeglass lens processing apparatus according to (9),further comprising:

[0035] a water supply unit for supplying the grinding water stored inthe tank to the processing chamber.

[0036] (11) The eyeglass lens processing apparatus according to (10),further comprising:

[0037] a water supply passage which connects the pump to the tank, andthrough which the grinding water sucked by the pump is supplied to thetank.

[0038] (12) A processing debris separating device for separatinggrinding water, used for processing an eyeglass lens and drained to atank, from processing debris, comprising:

[0039] a filter, disposed in the tank, for filtering the grinding waterto be separate from the processing debris, the filter having a sealedhollow portion;

[0040] a water suction pump; and

[0041] a water suction passage which connects the hollow portion to thepump, and through which the grinding water filtered by the filter issucked by suction of the pump.

[0042] (13) A grinding water tank unit which enables reuse of grindingwater that has been used for processing an eyeglass lens, comprising:

[0043] a first tank in which the grinding water is stored;

[0044] a filter for filtering the grinding water to be separate fromprocessing debris, the filter having a chamber in which the processingdebris is accumulated;

[0045] a pressurizing pump;

[0046] a water suction passage which connects the first tank to thepump, and through which the grinding water in the first tank is suckedby suction of the pump; and

[0047] a first water supply passage which connects the pump to thechamber of the filter, and through which the grinding water sucked bythe pump is supplied to the chamber under a predetermined waterpressure.

[0048] (14) The tank unit according to (13), wherein the filter isdisposed in the first tank.

[0049] (15) The tank unit according to (13), wherein the filter isdisposed in a second tank provided outside the first tank.

[0050] (16) The tank unit according to (15), further comprising:

[0051] a second water supply passage which connects the second tank tothe first tank.

[0052] (17) The tank unit according to (15), further comprising:

[0053] an anti-foaming device for eliminating bubbles developing in thefirst tank.

[0054] (18) An eyeglass lens processing apparatus for processing aneyeglass lens, comprising:

[0055] a processing chamber in which a lens grinding tool is disposed;

[0056] a tank in which grinding water is stored;

[0057] a drain passage through which the grinding water is drained fromthe processing chamber to the tank;

[0058] a filter for filtering the grinding water to be separate fromprocessing debris, the filter having a chamber in which the processingdebris is accumulated;

[0059] a pressurizing pump;

[0060] a water suction passage which connects the tank to the pump, andthrough which the grinding water in the tank is sucked by suction of thepump; and

[0061] a water supply passage which connects the pump to the chamber ofthe filter, and through which the grinding water sucked by the pump issupplied to the chamber under a predetermined water pressure.

[0062] (19) The eyeglass lens processing apparatus according to (18),further comprising:

[0063] a water supply unit for supplying the grinding water stored inthe tank, to the processing chamber.

[0064] (20) A processing debris separating device for separatinggrinding water, used for processing an eyeglass lens and drained to atank, from processing debris, comprising:

[0065] a filter for filtering the grinding water to be separate from theprocessing debris, the filter having a chamber in which the processingdebris is accumulated;

[0066] a pressurizing pump;

[0067] a water suction passage which connects the tank to the pump, andthrough which the grinding water in the tank is sucked by suction of thepump; and a water supply passage which connects the pump to the chamberof the filter, and through which the grinding water sucked by the pumpis supplied to the chamber under a predetermined water pressure.

[0068] The present disclosure relates to the subject matter contained inJapanese patent application Nos. 2001-202808 (filed on Jul. 3, 2001),2001-232203 (filed on Jul. 31, 2002) and 2001-232204 (filed on Jul. 31,2002), which are expressly incorporated herein by reference in theirentireties.

BRIEF DESCRIPTION OF THE DRAWINGS

[0069]FIG. 1 is an overall schematic diagram of an eyeglass lensprocessing apparatus according to a first embodiment;

[0070]FIG. 2 is a schematic diagram of an antifoaming device;

[0071]FIG. 3 is a view of a filter of the apparatus of the firstembodiment when viewed from a bottom surface of a tank;

[0072]FIG. 4A is a view showing a first modification of the antifoamingdevice;

[0073]FIG. 4B is a view showing a second modification of the antifoamingdevice;

[0074]FIG. 5 is a view showing an example in which a processing debrisseparator is constructed as a discrete device;

[0075]FIG. 6 is an overall schematic diagram showing an eyeglass lensprocessing apparatus according to a second embodiment;

[0076]FIG. 7A is a view showing a first modification of filter layout ofthe apparatus of the second embodiment; and

[0077]FIG. 7B is a view showing a second modification of filter layoutof the apparatus of the second embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0078] <First Embodiment>

[0079] An embodiment of the invention will now be described by referenceto the drawings. FIG. 1 is an overall schematic diagram of an eyeglasslens processing apparatus according to a first embodiment of theinvention. The processing apparatus is roughly constituted of aprocessing apparatus main unit 1; a table 100 on which the main unit 1is to be placed; and a circulation-type grinding water tank unit 200 tobe placed in the table.

[0080] Disposed in the housing of the main unit 1 is a processingsection 10 comprising two lens rotary shafts (e.g., chuck shafts) 2R, 2Lfor holding a lens LE to be processed; a carriage section 3 to which thelens rotary shafts 2R, 2L are rotatably attached; and a grinder 5attached to a rotary shaft 6 for processing the edge of the lens LE. Thegrinder 5 is constituted of three grinding stones: namely, a roughgrinding stone for plastics; a rough grinding stone for glass; and afinishing grinding stone having a groove for beveling and a flatprocessing surface. The grinder 5 is rotated by an unillustrated motor.The carriage section 3 is movable in the axial direction of the lensrotary shafts 2R, 2L, and also movable relative to the grinder 5. Formore details of the processing section 10, please refer to Reference No.35,898 (Japanese Patent Application Laid-Open No. 212661/1993).

[0081] A processing chamber 9 is defined by a waterproof cover 8disposed within the main unit 1 so as to enclose the lens LE to be heldby the lens rotary shafts 2R, 2L, as well as the grinder 5. A nozzle 11for spraying grinding water extends into the processing chamber 9. Thenozzle 11 is connected to a water suction pump 220 of a tank unit 200 bya water supply hose 221. During the course of processing of the lens LE,grinding water is sprayed out of the nozzle 11. The thus-sprayedgrinding water and processing debris 250 (grinding wastes) of the lensLE are drained into a grinding water reservoir tank 210 of the tank unit200 by way of a drain hole 8 a formed in a lower portion of the cover 8,and a drain hose 201.

[0082] The tank 210 has a cylindrical shape with a bottom, and isequipped with an unillustrated handle so as to be portable. The tank 210is not limited to a cylindrical shape but may be box-shaped.

[0083] A lid 211 for substantially hermetically sealing the inside ofthe tank 210 is removably fitted in an opening section formed in anupper part of the tank 210. A partition plate 230 to be used fordividing the inside of the tank 210 into a drainage chamber 210 a and awater suction chamber 210 b is fixedly provided in the vicinity of thecenter of the lid 211. As shown in FIG. 2, a clearance (i.e., opening)for ensuring a passage along which grinding water is to flow is formedbetween an interior side surface of the tank 210 and side edges of thepartition plate 230 and between an interior bottom surface of the tank210 and a lower edge of the partition plate 230 (the drainage chamber210 a and the water suction chamber 210 b are partially connected toeach other).

[0084] A connection opening 212 to which the hose 201 is to be connectedis formed in an area of the lid 211 located above the drainage chamber210 a. Grinding water introduced by the hose 201 is drained into thetank 210 by way of the connection opening 212. A water suction pipe 215is attached to an area of the lid 211 located above the water suctionchamber 210 b so as to extend downward. A filter 216 having a coarsemesh screen is attached to a water suction opening 215 a provided at thelower end of the pipe 215. A water suction hose 217 is connected to anupper end of the pipe 215 projecting from an upper surface of the lid211. The other end of the hose 217 is connected to the pump 220. Bydriving operation of the pump 220, the grinding water pumped up(acquired) by way of the pipe 215 is introduced to the nozzle 11 by wayof the hose 217 and the hose 221. Here, the connection opening 212 andthe water suction opening 215 a are preferably located as far aspossible from the partition plate 230.

[0085] The partition plate 230 is provided for purposes of hindering theprocessing debris 250 mixed in the drained grinding water in reachingthe water suction opening 215 a as well as facilitating the processingdebris 250 to be settled at the bottom of the tank 210. Accordingly, thepartition plate 230 may be dispensed with.

[0086] The tank unit 200 is equipped with an antifoaming device 300 foreliminating (breaking) bubbles 251 by spraying a fluid (e.g., grindingwater in this embodiment). The antifoaming device 300 has a watersuction pipe 301 attached to the lid 211 for sucking grinding water fromthe water suction chamber 210 b; a water suction pump 305; a watersuction hose 303 for connecting the pipe 301 to the pump 305; a nozzle310 for spraying the grinding water pumped by the pump 305 to thedrainage chamber 210 a; and a water supply hose 307 for connecting thepump 305 to the nozzle 310. A filter 302 having a coarse mesh screen isattached to a water suction opening 301 a formed at a lower end of thepipe 301.

[0087] The nozzle 310 is attached to an upper part of the partitionplate 230. As shown in FIG. 2, the nozzle 310 has the shape of a rod. Alarge number of spray openings 310 a are formed in a longitudinal sidesurface of the nozzle 310 so as to spray grinding water in asubstantially horizontal direction. The spray openings 310 a areprovided so as to situate in a position above a water surface whengrinding water is poured (stored) in the tank 210. In the case of thehorizontally long nozzle 310 such as that shown in FIG. 2, the sprayopenings 310 a are preferably provided in the entire area occupying fromthe center of the tank 210 to the vicinities of the interior sidesurface of the tank 210 so that sprayed grinding water can cover, to theextent possible, the inside of the tank 210 (i.e., the drainage chamber210 a). The grinding water supplied by the pump 305 by way of the hose307 is introduced from a connection opening 311 formed in the vicinityof the center of the nozzle 310 and sprayed at a predetermined waterpressure by way of the spray openings 310 a. The thus-sprayed grindingwater can suppress foaming of the bubbles 251 in the tank 210 (i.e., thedrainage chamber 210 a) The tank unit 200 is provided with a processingdebris separator 330 which facilitates settlement of the processingdebris 250 and separates grinding water from the processing debris 250.The processing debris separator 330 comprises a filter 331 provided onthe bottom of the tank 210; a water suction pump 333 for pumpinggrinding water stored in the tank 210 by way of the filter 331; a watersuction pipe 335 and a water suction hose 337 for connecting the pump333 to a hollow section 339 defined between the filter 331 and theinterior bottom surface of the tank 210; a connection opening 343 formedin a side surface of the tank 210; and a water-supply hose 341 forconnecting the pump 333 to the connection opening 343.

[0088] A sintered porous member is preferably employed as the filter331. The embodiment employs sintered porous plastic member produced bysintering plastic beads, by virtue of its lightweight, durability, andsuperior machinability. The sintered porous plastic member is formedprincipally from polyethylene, polypropylene,ethylene-vinyl-acetate-copolymer or the like. The embodiment employs afilter 331 having a pore size of about 15 μm. The present inventorconducted tests using a filter having a pore size of 15 μm and a filterhaving a pore size of 70 μm. The grinding water that has passed throughthe filter having a pore size of 70 μm was ascertained to cause awhitish turbidity. The 70 μm filter was confirmed to have low filteringaccuracy. When filtering was continued further with the 70 μm filter,minute processing debris was ascertained to clog the filter, therebylowering a filtering rate. In contrast, the filter having a pore size of15 μm was ascertained to produce transparent filtered grinding water andhave less effect on a filtering rate even when filtering operation wasperformed continuously. Accordingly, use of a filter having a pore sizesmaller than 70 μm (e.g., 15 μm or thereabouts) for the filter 331 ispreferable in terms of filtering accuracy and filtering rate.

[0089]FIG. 3 is an illustration of the filter 331 when viewed from thebottom surface of the tank 210. The filter 331 is disposed on the bottomof the tank 210 having a circular cross-sectional shape, and thereforehas the shape of a disk which is substantially identical in area withthe interior bottom surface of the tank 210. The filter 331 has athickness of 7 mm. A grid-shaped groove 331 a (the hatched portion inFIG. 3) having a depth of 2 mm is formed in the lower surface of thefilter 331 (i.e., the surface facing the interior bottom surface of thetank 210). A suction opening 331 b to be connected to the pipe 335 isformed in the center portion of the groove 331 a. The groove 331 aserves as a passage along which filtered grinding water flows, and isformed so that all portions of the groove 331 communicate with thesuction hole 331 b. The filter 331 is placed on the bottom of the tank210 such that the outer periphery of the filter 331 is bonded to theinterior side surface of the tank 210 in a shielding manner. The hollowsection 339 is established by the groove 331 a and the interior bottomsurface of the tank 210, thereby ensuring a passage for sucking oraspirating filtered grinding water.

[0090] The lower surface of the filter 331 is given a groove structurefor preventing occurrence of fracture or deformation in the filter 331,which would otherwise be caused by the weight of the processing debris250 settled (accumulated) on the upper surface of the filter 331 and theweight of the grinding water. Therefore, the groove structure is notinevitable. For instance, the lower surface of the filter 331 may bemade flat, and blocks may be disposed below the lower surface of thefilter 331 so as to ensure a groove 331 a similar to that shown in FIG.3, thereby forming the hollow section 339. Alternatively, a cloth filterhaving a mesh structure, such as a cotton filter, may be employed as thefilter 331. Even in this case, the only requirement is that areinforcement frame be disposed so as to constitute the hollow section339.

[0091] If the tank 210 is rectangular in a horizontal cross-sectionalshape, the filter 331 should also be rectangular.

[0092] Reference numeral 20 designates a control section provided in themain unit 1. The control section 20 is connected to the pumps 220, 305,and 333, as well as to a drive unit 22 for rotating the grinder 5 and adrive unit 21 for moving the carriage section 3.

[0093] Next, use of such an apparatus will be described. First, grindingwater is stored in the tank 210. At this time, a water surface is set soas to become one to two centimeters lower than the nozzle 310 of theantifoaming device 300.

[0094] When the main unit 1 has started processing the lens LE, thecontrol section 20 drives the pump 220, whereby the grinding waterpumped from the water suction chamber 210 b is sprayed into theprocessing chamber 9 by way of the nozzle 11. The thus-sprayed grindingwater and the resultant processing debris 250 of the lens LE are drainedinto the drainage chamber 210 a by way of the drain hole 8 a and thehose 201.

[0095] At the time of processing of the lens, the pump 333 is activatedby a switch 25 connected to the control section 20, in order to promotesettlement of the processing debris 250 in the tank 210. Here, thecontrol section 20 may perform a control operation so as to drive thepump 333 in conjunction with driving action of the pump 220.

[0096] When the pump 333 is activated, suction pressure is exerted onthe hollow section 339 formed below the filter 331, whereby the grindingwater stored in the tank 210 is sucked or aspirated and filtered by wayof the filter 331. The grinding water pumped by the pump 333 is returnedto the tank 210 from the connection opening 343 by way of the hose 341.By this suction, the processing debris 250 are attracted toward thefilter 331, whereby settlement of the processing debris 250 is promoted.Further, progress in solidification of the thus-settled processingdebris 250 inhibits generation of turbidity in the grinding water storedin the tank 210. Hence, a large amount of processing debris 250 can beaccumulated in the tank 210. The processing debris 250 is settled inorder of larger size and weight. Accordingly, large processing debris250 is settled (accumulated) first on top of the filter 331. Hence,clogging of the filter 331 is prevented, and the thus-settled(accumulated) processing debris 250 acts as a new filter.

[0097] A permissible storage amount of processing debris 250 in the tank210 is such a level that settled processing debris 250 is not suckedinto the suction openings 215 a, 301 a (via the filters 216, 302).Although it depends on the height of the location where the suctionopening 215 a or the like is formed, if about 5 to 6 liters ofprocessing debris 250 can be settled in a 20-liter tank, about 200lenses can be processed.

[0098] A filtering rate of the filter 331 is high at the beginning of afiltering operation. However, as a result of the processing debris 250deposited on the filter 331, the filtering rate decreases. The filteringrate is also sensitive to the performance of the pump 333. Even when ahigh-power pump is used as the pump 333, an increase in the quantity offlow (i.e., a flow rate) leads to a sharp rise in a loss stemming fromflow of the grinding water through the filter 331 (i.e., a flow loss).For this reason, driving of the pump 333 with appropriate suction ispreferable in terms of preventing overload. The eyeglass lens processingapparatus adopts as the pump 333 a gear pump using a DC motor, and thepump is activated with a constant current. In the case of low filterresistance (flow loss), such a pump achieves at a higher rotationalspeed and a larger flow rate. In contrast, when load on the motorbecomes high as a result of increase in filter resistance, the motoroperates at a low current and is controlled so as to reduce therotational speed of the motor, thereby preventing overload.

[0099] With a view toward controlling generation of bubbles during thecourse of processing of a plastic lens, an antifoaming agent is usuallyadded to the grinding water stored in a circulation-type tank unit.However, when the grinding water including an antifoaming agent isfiltrated using the filter 331, the filtering performance of the filter331 is greatly deteriorated by a surfactant included in the antifoamingagent. The reason for this is that processing debris enters and clogsthe filter 331. In order to prevent this adverse effect, the eyeglasslens processing apparatus does not employ any antifoaming agent.However, if no antifoaming agent is used, processing of few plasticlenses (e.g., 20 to 30) would involve generation of a large amount ofbubbles, thereby requiring frequent replacement of grinding water.

[0100] The eyeglass lens processing apparatus eliminates the bubbles 251by use of an antifoaming device 300. The pump 305 is activated inconjunction with driving action of the pump 220 so that the grindingwater is sprayed from the spray openings 310 a of the nozzle 310 to thedrainage chamber 210 a as a shower. The thus-sprayed water comes intocollision with the bubbles at a predetermined water pressure, therebybreaking the bubbles. In this way, the processing debris which isincluded in the bubbles and can be settled is separated, and thethus-separated debris can be settled.

[0101] The configuration and layout of the nozzle 310 are not limited tothose described previously. The nozzle 310 may have, for example, thefollowing configurations. FIGS. 4A and 4B show modifications of theantifoaming device 300. A nozzle 313 shown in FIG. 4A has ahemispherical shape, and a large number of spray openings 313 a areformed in the hemispherical surface. A connection opening 314 isattached to the lid 211 such that the nozzle 313 is situated in thevicinity of the center of the drainage chamber 210 a. The grinding watersupplied from the pump 305 is sprayed from the spray openings 313 a ofthe nozzle 313 by way of the hose 307 and the connection opening 314 tobe ejected toward the bubbles in the tank 210 at a predetermined waterpressure. Further, if the apparatus is provided with a mechanism forrotating the nozzle 313 so as to change the spraying direction, thegrinding water will be sprayed so as to be distributed over the entireinside of the tank 210 (the drainage chamber 210 a), thereby eliminatingbubbles more efficiently. A rotary mechanism which undergoes rotation byuse of a motor, water pressure, or reactive force of a jet can beemployed as a mechanism for rotating the nozzle 313.

[0102] A nozzle 320 shown in FIG. 4B is an example of a rotary-typenozzle utilizing reactive force of a jet. A rotary shaft support 321 isattached to the connection opening 314 shown in FIG. 4A. Threerod-shaped nozzles 320 are attached to the rotary shaft support 321.Spray openings 320 a are formed in one side surface of each nozzle 320.The nozzle 320 is rotated along with the rotary shaft support 321, bymeans of reactive force of the grinding water sprayed from the sprayopenings 320 a.

[0103] Even in the case of the nozzle 310 shown in FIGS. 1 and 2, if amechanism, such as a motor for pivoting the nozzle 310, is provided andthe angle at which grinding water is to be sprayed from the sprayopenings 310 a is repeatedly changed between a horizontal direction anda slightly-downward direction, elimination of bubbles can be performedmore efficiently. The antifoaming device may be constructed such thatbubbles are mechanically agitated by rotating a rotary member havingrod-shaped arms. Such an antifoaming device breaks bubbles by the armsof the rotary member coming into collision with the bubbles.

[0104] There will now be described an operation in which the processingdebris 250 stored in the tank 210 is discarded. In this case, the hose341 is disconnected from the connection opening 343, and the grindingwater pumped by the pump 333 is drained to the outside without beingreturned to the tank 210. The grinding water pumped by the pump 333 issufficiently filtered by the filter 331 and hence can be draineddirectly. Alternatively, the grinding water may be poured into aseparately prepared water receiver tank for the purpose of recycling.When the pump 333 is activated by turning on the switch 25, the grindingwater stored in the tank 210 is gradually pumped and drained to theoutside by way of the filter 331. Finally, moisture contained in theprocessing debris 250 is also subjected to suction. When the moisturecontent in the processing debris 250 is reduced, the processing debris250 are subjected to cracking, whereupon air is directly as pirated byway of the filter 331. Hence, suction of grinding water becomesimpossible. When no grinding water is drained, the pump 333 isdeactivated.

[0105] When suction of grinding water has become impossible, theprocessing debris 250 have a water content of about 40 to 50%, and theprocessing debris 250 is solidified. The thus-solidified processingdebris 250 can be readily removed from the tank 210 by simply turningthe tank 210 upside down. The processing debris 250 are discarded whilebeing held in a plastic bag or the like. If the water content is 50% orless, no water seeps through the processing debris 250, therebyfacilitating discarding of the processing debris 250. When the watercontent of the processing debris 250 is to be decreased further, theprocessing debris 250 is left so as to become naturally dried. Thethus-discarded processing debris 250 is to be disposed by an industrialwaste disposal company.

[0106] The processing debris separator 330 comprising the filter 331,the pump 333, and the like is provided in the circulation-type tank unit200 to be integral with the tank 210. However, the processing debrisseparator 330 may be provided separately. FIG. 5 shows an example ofsuch a configuration. Reference numeral 350 designates a cylindricalfilter made from sintered porous plastic member. Lids 352, 353 are fixedto respective ends of the filter 350, thereby defining a hollow section351 in the filter 350. A water suction pipe 355 to be connected to thehollow section 351 is attached to the lid 352. The pipe 355 is connectedto a water suction pump 357 by a water suction hose 356. The grindingwater pumped by the pump 357 is drained by way of a drain hose 358. Whenthe processing debris 250 accumulated in the tank 210 is discarded, thefilter 350 is inserted into the tank 210. The pump 357 is thenactivated, thereby pumping the grinding water in the tank 210 whilefiltering and draining, whereby the processing debris 250 can beseparated and removed.

[0107] When separation of grinding water from processing debris ispromoted, a plurality of such filters 350 should be prepared. As amatter of course, if a plate for sealing purpose is secured on thebottom of the filter 331 so as to ensure the hollow section 339 throughuse of the plate-like filter 331 shown in FIGS. 1 and 3, the filter canbe used solely. Alternatively, the filter 350 may be provided in a tankprepared separately from the tank 210, and grinding water including theprocessing debris 250 may be poured into the tank, thus separating thegrinding water from the processing debris 250.

[0108] <Second Embodiment>

[0109] Another embodiment of the invention will be describedhereinbelow. FIG. 6 is an overall schematic diagram showing an eyeglasslens processing apparatus according to a second embodiment of theinvention. Those elements which are identical with those described inconnection with the first embodiment are assigned the same referencenumerals.

[0110] A downwardly extending water suction pipe 231 is provided at aposition on one side of the lid 211 opposite from the other side thereofwhere the pipe 215 is provided. A water suction opening 231 a providedat the lower end of the pipe 231 is extended to a lower position in thetank 210. A filter 232 having a coarse mesh screen is attached to thewater suction opening 231 a so as to sink to the bottom of the tank 210.Positioning the water suction opening 231 a close to the neighborhood ofthe bottom of the tank 210 to the extent possible is preferable, and thewater suction opening may be formed in the bottom of the tank 210. Inaddition, the filter 232 may be eliminated.

[0111] A water suction hose 233 is connected to an upper end of the pipe231 projecting beyond the upper surface of the lid 211. The other end ofthe hose 233 is connected to a pressure application pump 236 foraspirating (pumping) the processing debris 250 along with grindingwater. Moreover, a water supply hose 234 for feeding the thus-aspiratedgrinding water and the processing debris 250 is connected to the pump236. A drain hole 234 a provided at the other end of the hose 234 isextended to the lid 211 and connected to a bag-shaped filter 235provided in the tank 210. Thus, there is formed a passage to be used forremoving and introducing the processing debris 250 that have settled inthe tank 210 along with the grinding water, which extends from the watersuction opening 231 a to the filter 235. The pump 236 disposed at aportion of the passage between the water suction opening 231 a and thefilter 235 applies a water pressure of about at least 0.05 Mpa onto thegrinding water including the processing debris 250 to charge the sameinto the filter 235.

[0112] The filter 235 is constituted of a cotton cloth having a finemesh screen. The filter 235 preferably does not permit passage ofprocessing debris of small particle size (on the order of micrometers)and prevents inclusion of any processing debris in filtered water. Anopening end of the filter 235 is bundled at the drain hole 234 a of thehose 234 and fastened with a binding band 237. As a result, the filter235 is connected to the drain opening 234 a in a substantially-sealedmanner. The filter 235 is separated from the drain hole 234 a by removalof the band 237 and can be removed from the tank 210.

[0113] The filter 235 is not limited to the shape of a bag and may haveany shape, so long as the filter can form a chamber for accumulating theprocessing debris 250 therein.

[0114] The drive unit 21, the drive unit 22, the pump 220, and the pump236 are connected to the control section 20.

[0115] Next will be described use of the eyeglass lens processingapparatus discussed above. Since processing debris 250 of a plastic lensand a glass lens is, in general, is heavier than water, the processingdebris 250 is settled on the bottom of the tank 210. When the lenses LEare processed consecutively, the amount of processing debris 250 settledin the tank 210 increases.

[0116] The pump 236 is activated by the switch 25 (or in conjunctionwith the driving action of the pump 220), and the processing debris 250settled on the bottom of the tank 210 are aspirated from the watersuction opening 231 a by way of the filter 232 along with the grindingwater. The grinding water including the thus-aspirated processing debris250 flows through the pipe 231 and the hose 233, is pressurized to apressure of about 0.06 Mpa by the pump 236, and is charged into thefilter 235 by way of the hose 234. The filter 235 does not permitpassage of processing debris of fine particles and accumulates thedebris 250 therein. Substantially-purified grinding water is dischargedto the outside (into the tank 210) so as to seep through the surface ofthe filter 235.

[0117] Here, if the filter 235 having a fine mesh screen and highfiltration capability is simply used for filtering grinding water, muchtime will be consumed. For example, if the filter 235 is connected tothe hose 201, filtering operation involves consumption of much time. Thehose 201 may become clogged with the grinding water, which would causeleakage of grinding water into the processing chamber 9. In contrast,the pump 236 applies a water pressure of about at least 0.05 Mpa ontothe processing water charged into the filter 235. Hence, a filteringrate can be increased significantly. Since the filtering rate can beincreased by use of a filter of identical capacity, the rate of recoveryof the processing debris 250 settled in the tank 210 is enhanced.Further, soil content of the processing water supplied to the main unit1 can be decreased.

[0118] If processing of lenses and filtering operation are performedrepeatedly, the processing debris 250 is stacked on the interior surfaceof the filter 235. If processing of lenses is continued further, thethus-stacked processing debris 250 per se acts as a filter. Hence,processing debris which are smaller than the screen mesh of the cottoncloth of the filter 235 can be accumulated in the filter 235. By virtueof the stacked processing debris acting as a filter of smaller screenmesh, filtering grinding water requires a longer time. However, waterpressure is exerted on the grinding water charged into the filter 235 bythe pump 236, and hence consumption of along filtering time is notinvolved.

[0119] If the pump 236 is operated continuously even after completion ofprocessing of a lens, the processing debris 250 contained in thegrinding water can be accumulated in the filter 235 even when processingof a lens is halted. In this case, the pump 236 may be controlled usinga timer so as to be operated for a given period of time after completionof processing of a lens and then be deactivated automatically. Thecontrol section 20 may be given such a timer function. Further, thecontrol section 20 may repeatedly activate and deactivate the pump 236after completion of processing of the lens so as to cause repeatedexpansion and contraction of the filter 235, whereby the processingdebris 250 stacked on the interior surface of the filter 235 is peeledand accumulated on the bottom of the filter 235. As a result, even ifclogging has induced a decrease in a filtering rate, the filtering ratecan be restored.

[0120] When the processing debris 250 accumulated in the filter 235 isdiscarded, the lid 211 is raised, and the filter 235 is removed from theinside of the tank 210. The band 237 of the drain opening 234 a is thenremoved, and the filter 235 is separated. The thus-separated filter 235is further drained, thereby solidifying the processing debris 250contained in the filter 235. Hence, disposal of the processing debris isfacilitated. The processing debris 250 may bed is carded together withthe filter 235 containing the processing debris therein. Alternatively,only the processing debris 250 may be discarded, and the filter 235 maybe reused.

[0121] The filter 235 may be placed at a position above the watersurface of the grinding water stored in the tank 210 so that the insideof the filter 235 is drained at a time other than when the pump 230 isactivated. In this case, the efficiency of processing the processingdebris 250 can be enhanced.

[0122]FIGS. 7A and 7B show modifications of layout of the filter 235.FIG. 7A shows an example in which the filter 235 is placed outside (ontop of) the tank 210. The grinding water filtered by the filter 235 isdrained to the outside of a tank 260 enclosing the filter 235. The tank260 is placed in a position higher than the tank 210. Hence, thefiltered grinding water can be returned to the tank 210 through naturaldropping action (gravity) by way of a water supply pipe 261 connectingthe tank 260 to the tank 210. FIG. 7B shows an example in which thefilter 235 is placed outside (beside) the tank 210. The grinding waterfiltered by the filter 235 is drained into a tank 263. In this case, apump 262 is disposed between a water suction hose 264 and a water supplyhose 265 for connecting the tank 263 to the tank 210, thereby returningthe filtered grinding water into the tank 210. FIGS. 7A and 7B showexamples in which the filter 235 is placed outside the tank 210. Hence,the processing debris 250 can be drained within a short period of timeafter deactivation of the pump 230, thereby enhancing efficiency forprocessing the processing debris 250.

[0123] In addition, the antifoaming device 300 of the first embodimentmay be disposed in the eyeglass lens processing apparatus of the secondembodiment.

[0124] As has been described, the invention enables easy separation ofgrinding water and processing debris in a tank. Hence, processing debriscan be processed readily. Bubbles in a tank can be reduced without useof an antifoaming agent, and the frequency of replacement of grindingwater can be diminished.

What is claimed is:
 1. A grinding water tank unit which enables reuse ofgrinding water that has been used for processing an eyeglass lens,comprising: a tank in which the grinding water is stored; a filter,disposed in the tank, for filtering the grinding water to be separatefrom processing debris, the filter having a sealed hollow portion; afirst water suction pump; and a first water suction passage whichconnects the hollow portion to the first pump, and through which thegrinding water filtered by the filter is sucked by suction of the firstpump.
 2. The tank unit according to claim 1, wherein the filter includesa substantially plate-like filter which is disposed at a bottom of thetank, and which has a filter surface substantially equal in area to aninterior bottom surface of the tank.
 3. The tank unit according to claim2, wherein the filter has the hollow portion defined between the filterand the interior bottom surface of the tank.
 4. The tank unit accordingto claim 1, further comprising: a first water supply passage whichconnects the first pump to the tank, and through which the grindingwater sucked by the first pump is supplied to the tank.
 5. The tank unitaccording to claim 1, further comprising: an antifoaming device foreliminating bubbles developing in the tank.
 6. The tank unit accordingto claim 5, wherein the antifoaming device has a water ejection openingdisposed at a predetermined height in the tank, and eliminates thebubbles using water pressure of water ejected from the water ejectionopening.
 7. The tank unit according to claim 6, further comprising: asecond water suction pump; a second water suction passage which connectsthe tank to the second pump, and through which the grinding water in thetank is sucked by suction of the second pump; and a second water supplypassage which connects the second pump to the water ejection opening,and through which the grinding water sucked by the second pump issupplied to the water ejection opening.
 8. The tank unit according toclaim 6, wherein an ejection direction of the water ejection opening ischangeable.
 9. An eyeglass lens processing apparatus for processing aneyeglass lens, comprising: a processing chamber in which a lens grindingtool is disposed; a tank in which grinding water is stored; a drainpassage through which the grinding water is drained from the processingchamber to the tank; a filter, disposed in the tank, for filtering thegrinding water to be separate from processing debris, the filter havinga sealed hollow portion; a water suction pump; and a water suctionpassage which connects the hollow portion to the pump, and through whichthe grinding water filtered by the filter is sucked by suction of thepump.
 10. The eyeglass lens processing apparatus according to claim 9,further comprising: a water supply unit for supplying the grinding waterstored in the tank to the processing chamber.
 11. The eyeglass lensprocessing apparatus according to claim 10, further comprising: a watersupply passage which connects the pump to the tank, and through whichthe grinding water sucked by the pump is supplied to the tank.
 12. Aprocessing debris separating device for separating grinding water, usedfor processing an eyeglass lens and drained to a tank, from processingdebris, comprising: a filter, disposed in the tank, for filtering thegrinding water to be separate from the processing debris, the filterhaving a sealed hollow portion; a water suction pump; and a watersuction passage which connects the hollow portion to the pump, andthrough which the grinding water filtered by the filter is sucked bysuction of the pump.
 13. A grinding water tank unit which enables reuseof grinding water that has been used for processing an eyeglass lens,comprising: a first tank in which the grinding water is stored; a filterfor filtering the grinding water to be separate from processing debris,the filter having a chamber in which the processing debris isaccumulated; a pressurizing pump; a water suction passage which connectsthe first tank to the pump, and through which the grinding water in thefirst tank is sucked by suction of the pump; and a first water supplypassage which connects the pump to the chamber of the filter, andthrough which the grinding water sucked by the pump is supplied to thechamber under a predetermined water pressure.
 14. The tank unitaccording to claim 13, wherein the filter is disposed in the first tank.15. The tank unit according to claim 13, wherein the filter is disposedin a second tank provided outside the first tank.
 16. The tank unitaccording to claim 15, further comprising: a second water supply passagewhich connects the second tank to the first tank.
 17. The tank unitaccording to claim 15, further comprising: an anti-foaming device foreliminating bubbles developing in the first tank.
 18. An eyeglass lensprocessing apparatus for processing an eyeglass lens, comprising: aprocessing chamber in which a lens grinding tool is disposed; a tank inwhich grinding water is stored; a drain passage through which thegrinding water is drained from the processing chamber to the tank; afilter for filtering the grinding water to be separate from processingdebris, the filter having a chamber in which the processing debris isaccumulated; a pressurizing pump; a water suction passage which connectsthe tank to the pump, and through which the grinding water in the tankis sucked by suction of the pump; and a water supply passage whichconnects the pump to the chamber of the filter, and through which thegrinding water sucked by is the pump is supplied to the chamber under apredetermined water pressure.
 19. The eyeglass lens processing apparatusaccording to claim 18, further comprising: a water supply unit forsupplying the grinding water stored in the tank, to the processingchamber.
 20. A processing debris separating device for separatinggrinding water, used for processing an eyeglass lens and drained to atank, from processing debris, comprising: a filter for filtering thegrinding water to be separate from the processing debris, the filterhaving a chamber in which the processing debris is accumulated; apressurizing pump; a water suction passage which connects the tank tothe pump, and through which the grinding water in the tank is sucked bysuction of the pump; and a water supply passage which connects the pumpto the chamber of the filter, and through which the grinding watersucked by the pump is supplied to the chamber under a predeterminedwater pressure.